The present invention relates to a plant for the separation at high temperatures of contaminants of various types from plastic material in small pieces or in leaves.
This is a need which is particularly felt during processes for the recycling of plastic material: the material must in fact be freed of different contaminants such as for example paper, glue, wood and, more generally, various types of fibres.
The existence of a centrifugal dryer is also known as being particularly suitable for plastic material in small pieces previously washed. This dryer has been described in the Gazzoni, U.S. Pat. No. 4,441,262, issued Apr. 10, 1984.
It has also been seen that the dryer can be used as a device for separating contaminants from plastic material in small pieces or leaves.
This operation is rendered particularly effective if performed at high temperatures using water and steam, with chemical additives if required, as a fluid for conveying the material along the plant.
The use of steam as a component of the conveying fluid however entails high costs both in energy terms and in terms of equipment for producing the steam itself.